Time domain dielectric study of non-ionic microemulsions

The dielectric behavior of a microemulsion prepared from dodecane, butanol, water and polyoxyethylene (10) oleylalcohol (Brij 97) has been studied by time domain dielectric spectroscopy over the frequency range of 10⁵-10¹⁰ Hz for temperatures between 10 and 40°C with varying water content. Several dielectric dispersion regions with the typical characteristic relaxation times of the order of nanoseconds and tens of picoseconds are observed. They are analyzed in time domain in terms of macroscopic dipole correlation functions and are attributed to the relaxation mechanisms of the different chemical compounds within the microemulsion. The appearance and intensity of the peaks for the relaxation processes depend on the water content. The types of motion of different kinetic units that can be manifested as local relaxation processes are proposed. The dielectric properties of microemulsions depend on the underlying phase behavior and on the consequent morphology in these systems. The results suggest that changes in the microstructure of polarization and relaxation mechanisms occur in the water fraction content intervals of 5-10, 10-35 and 35%.